"For $10 to $13 an hour, it's basically like going to a yoga class," she said. "Every class sells out. That speaks to the demand." (For more information: http://girldevelopit.com/chapters/philadelphia).
Her organization isn't the only one aiming to close the gender gap in computer technology, where, federal data indicate, men outnumber women, 2-1.
Part of it is a pipeline problem: Only one in five students who take the Advanced Placement Computer Science test are girls, even though they make up nearly half the group taking the AP Calculus exam, and less than one in five college computer-science majors are women.
Experts say it's key to influence girls while they are still in middle school, which is why, in 2009, Tracey Welson-Rossman began TechGirlz.
"Girls are self-selecting out of technology around ninth grade," Welson-Rossman said. "To them, it's not collaborative, not creative, and it also looks like what they think . . . a nerd looks like."
Meeting monthly, TechGirlz's middle-school-age members connect to technology through hands-on projects. Last Saturday, they learned KODU, a game-creation language.
Welson-Rossman, a founder of Chariot Solutions, a Philadelphia-based software-development company, sees encouraging young women to aim for computer-tech professions as a national imperative, with job openings dramatically outstripping qualified workers in the next decade.
"This is something that's really important for the fabric of our country," she said. Her company "wants to hire women, but we aren't seeing enough female candidates."
EBay agrees. On Monday, TechGirlz ( www.techgirlz.org) announced that it had received a $5,000 grant from eBay Foundation Corporate Advised Fund at Silicon Valley Community Foundation to develop afterschool programs for girls.
One of the TechGirlz is Nala Bailey, 14, of Marlton. She always liked mathematics, but now her grades are higher, and she said she's more confident about her ability to tackle tough problems.
"Most girls think we're smarter than guys," she said, adding that girls don't always put those smarts to use. "I think girls lean more toward fashion."
Bailey said she leans toward science and technology and aims to enter that field as a grown-up.
"I like the way TechGirlz makes me think about stuff. It makes me think about all the possibilities that girls from my generation can figure out with science for the next generation and to help our nation go on to the next step."
Mustafa, who also serves on the TechGirlz board, said Girl Develop It classes help women gain skills and confidence.
Shannon Baffoni, 27, of Philadelphia, took her first class so that she could fix minor coding mistakes she found as a quality tester.
"I could use the lingo. It gave me a little bit more confidence," she said.
The courses provided her with the skills to pursue a new passion and a new job as a website developer for a local advertising agency.
Baffoni said she has taken mixed-gender classes but prefers the Girl Develop It approach.
"You didn't feel anyone was judging. You didn't have anything to prove. You were just there because you wanted to learn," she said.
"GDI makes it a point to be very welcoming. It's OK to ask questions, it's OK to mess up, it's OK to not know what to do."
Contact Jane Von Bergen
at jvonbergen@ phillynews.com, @JaneVonBergen on Twitter, or at 215-854-2769. Read her workplace blog at www.philly.com/jobbing .